Boiler



W. L. R. EMMET.

BOILER.

APPLICATION FILED DEC. 12| |912- RENIEWEDy DEC. 3. 19|5.

l l 94, l 57. Patented Auwl 8, 1916.

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Witnesses I Tw Mentor William L @Emmet lliS oqttowweg W. L. R. IIVIIVIET.

BOILER.

V APPLICATION FILED DEC. I2, 1912- RENEWED DEC. 3. ISIS.. I Ll 94,157. i Patented Aug. 8,1916.

3 SHEETS-SHEET 2 Inventor I William L REmmet,

Witnesses.:

W. L.- R. EMMET.

BOILER. 'APPLICATION FILED DEC.2.1912 RENEWED DEC. 3.1915- 1,194,157.

Patented Aug. 8, 1916.

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, Inventor: WilliamLREmmet, b5

Wltnesses.

jy@ a '.Qwv Hisoflttorneg rca WILLIAM L. R. EIVIMET, OF SCHENECTADY, NEW YORK, ASSIGNOR T GENERAL ELECTRIC COMPANY, A. CORPORATION 0F NEWYORK.

BGILER.

Specication of'Letters Patent.

Patented Aug; Si, rigid.

Applicationled December 12, 1912, Serial No. 736,323?. Renewed December 3, 1915. Serial No. @$37.

T 0 all whom t may concer/'nf Be' it known that I, WHLIAM L. R. EM- MET, a citizen of the United States, residing at Schenectady, county of Schenectady,

State of New Yorkhave invented certainl The efficiency of processes by which power is generated by the expansion of vaporized liquids depends upon the range of tempera ture through which the vapor can act in a saturated condition, and it is with a view to extending the range available with steam that the use of mercury is proposed, the purpose being to Work the mercury through a temperature range above that conveniently available with steam and to condense the mercury vapor in a steam boiler so that the heat delivered maybe used as it now is in an ordinary condensing or non-condensing steam process.

Mercury vaporizes at atmospheric pressure with a temperature of 677 F. and condenses i av vacuum of 28 at about 457 F. Since leakage of mercury would involve loss and other difficulties, it is desirable to vaporize the mercury at a low pres-y atmosphere, and from the ligures above'.

given, it may be seen that ay temperature range of over. 200o F. is available without exceeding atmospheric pressure or going below a convenient degree of vacuum and that the temperature of condensation is still above that generally used in steam processes.

lVith a boiler suited to the edective vaporization ofmercury without the use of an excessive quantity ofthe liquid, the process of turning heat into power is relatively simple since the high vapor density of th'e mercury and relatively low power per pound of material gives a -low jet velocity which is convenientlyT applicable t`o drive a turbine of very simple construction. By placing the mercury turbine and steam boiler slightly above the level of l the mercury boiler, the condensed fluid can be drained back by gravity so that vno pumps will be required and so that the system is completely closed except for the ypackings on the mercury turbine lshaft, which packings can be effectively sealed to prevent the loss of mercury.

The volume of mercury vapor required in the process above described is -many times as great as that of the steam and this fact, combmed with the high cost of mercury, makes necessary a boiler construction very 'different from that used with steam. Inl

storage space steam boilers, that is, boilers havmg a space in which steam is stored, the liquid generally covers the heating surface and the vapor rises as bubbles through the liquid or accompanies a stream of the liquid induced by ebullition which constantly wets the heating surface and withdraws heat from it. In producing so large a volume of` vapor as is required in the mercury boiler, very ample space for the circulation of-liq uid would have to be provided if an action similar to that of the steam boiler was sought, and to fill such a space with liquid mercury would involve a prohibitive cost.

of/air on heated surfaces show' that with reasonable velocities an adequate'rate of removal can be maintained by the mercury vapor in contact with the heating surface without incurring serious pressure dili'erences. contact with. any part of the heating surface, it would superheat, and while it would again saturate on coming in contact with the liquid, this action would involve higher temperatures of the heating surface and If, however, vapor alone moved inl Yec lower efliciency. If, however, the conditions are such that the vapor moving in Contact with the heating surface isfaccompanied by f a suficient amount of liquid in a finely divided state, this liquid will itself take up heat from the heating surface and will, by vaporization, absorb the heat which is taken up by the moving vapor. Such a combined action of the liquid and vapor is accomplished by the design of boiler here shown and described.

In the accompanying drawingswhich are illustrative of my invention, Figure l is a longitudinal section of my improved boiler;

Fig. 2 is an enlarged vsectional view of the boiler; Fig. 3 is an enlarged detail view'of two of the tubes; Fig. 4 is a detail view of.

a slight modification of the tube structure; 5 Fig. 5 is a sectional detail view of a heater for heating .the mercury prior to its introduction into the boiler proper; Fig. 6 shows a modified construction of the cores for the heater; and Fig. 7 a modified construction of the cores for the boiler.'

6 indicates a metal. shell of any suitable construction containing the boiler tubes 7 and provided with a suitable heating means. As shown a grate 8 is arranged in the front of the shell to support a coal fire in the ordinary manner. The rear end ofthe shell is extended to receive the heater 9 which in- This is effect forms a part of the boiler. subjected to the flue gases after they have passed between the boiler tubes and given up heat thereto. The gases are collected in a hood 10 at the end of the shell and from said hood Athey pass by the conduit 11y to the chimney 12. In the conduit I may insert a Thus the heat of the flue gases is absorbed first by the boiler and then by the heater and economizer, said gases flowing through them Tin series.

The shell is provided with a tube sheet 12a in which the tubes 7 are supported in a vertical or substantially Vertical' position as will appear more fully hereinafter. Above said sheet is a vapor chamber 13 communieating by the pipe14 with a mercury vapor turbine. The heater 9 is composed of vertical tubes 15. that are supported between heads 16 and 17 as, will appear later. Mercury in liquid form is fed to thel heater by gravity from the pipe 18', the latter being connected at its other endto the mercury vapor condenser of the turbine driven Iby the vapor generated in the boiler. In this pipe is a trap 19 the legs of which should be y at least thirty inches long to actas a seal to prevent the boiler from forcing mercury or vapor upward through theL pipe 18, it bel ing remembered that the boiler is working .under'a'tmospheric' pressure vor a pressure slightly below it. To the left-hand end of `the heater is connected a pipe 20 to conveyl heated mercury therefrom to the hottest end` of the boiler. Thel boiler end of thepipe opens into the vapor chamber 13 and the 56 mercury flowing therefrom is free to flowvr over the tube sheet 12a and run into the tubes. i

Referring to Figs. 2 and 4.3 7 indicates the vertically disposed tubes which are closed at their lower ends and at their upper ends arey expanded or otherwise secured to the tube sheet 12". Inside of each tube is a core 421 offclay, hydraulic cement or other cheap .material which is heat resisting to a greater or less degree. The periphery and lower.`

feed water heater 11 for a steam boiler. A

-large area exposed to the hot tube and a small transverse connecting passage or space 24. The upper end ofthe core is provided with a V-shaped opening 25 forming a cup to receive mercury from the chamber on the upper side of the tube sheet. The center of the core is provided with a passage '25 through which mercury in liquid form is fed by gravity to the annular vertical space 23.` The cores are held in place by clamps 26 that are secured by `screws or bolts 27 or equivalent means. Each clamp has downturned ends engaging the V-Jshaped openings in two ladjacent cores so that one clamp suffices for both.I Instead of using a number of small projections the cores may be provided with spiral ribs 22a as shown in Fig. 7 which perform thesame ofiice. Being thin .they do not appreciably cut up the annular vaporizing spaces 23.

4In Fig. l is shown a slight modification of the core structure. 28 indicates a tubular envelop or casing made of some metalv unaffected by mercury in which the core is located. The core may with advantage be inserted in the envelop in a plastic condition and afterward permittedto harden. The ends of the envelop are closed by heads or 'caps 29. The envelop and lower head are provided with projections 22 that serve to center the core and form vthe spaces 23 and 24 previously referred to. This arrangement Awhile somewhat more expensive to construct hasthe advantage of greater accuracy so that the central passage and outer space can be made to strictly conform to the requirements. The cores are held in place by clamps 26 as before.

The action of the boiler is as follows: The

. supply of mercury in the system is approximately enough to fill allA the annular spaces 23 and the central passages 25a together with the cups at their upper ends. When no heat is applied' the mercury will fill all these passages l,by gravity, the tube sheet 12a being `placed in a horizontal position. When heat is applied a part ofthe mercury in 'the annular spaces surrounding the cores will be vaporized, which vapornvith the liquid that accompanies it will be forced up into the .vapor chamber 13,'the rapidity of this action 'depending upon the amount of heat 'suplll 15 which are open at both ends. These tubes need .not be strictly vertical. The main thing is to so arrange them that mercury can be fed thereto by gravity. Insidel of each tube is a core made of clay or hydraulic cement which is provided with peripheral projections 31 that serve to center it and form an annular space 32 for the mercury to be heated prior to its entrance into the boiler proper. The end of each core is provided withcne or more projections 33 to support the core and provide aA space for the mercury. The tubes may and usually would be arranged in sets through which the mercury flows in series, the tubes of each set being connected in multiple as regards the passage of mercury. The right-hand tube receives mercury from the opening 34: communicating with the chamber 35 which receives mercury from the trap 19 previously referred to. It flows downwardly through the annular space in each tube 0f the first set to the `connecting passage 36 at the bottom from which it flows upwardly through the annular passages of the second set to the top connecting passage 37. From this passage the mercury flows downwardly through the third set of tutes and so on. By reason of this arrangement the mercury will pick 'up a large amount of heat in its passage to the boiler. This action is facilitated by the fact that the annular passages 32 are relatively thin, measured .in a plane perpendicular to `the core, and the heating surface-of the tubes relatively large being similar in this respect to the boiler tubes. The passages should however be large enough to admit free iiow of the fluid without excessive friction. The mercury after being thoroughly heated enters thechamber 38 from which it Hows by the pipe 20 to the boiler proper as I hereinbefore explained. As arranged the liquid enters the heater at the end remote from the lire where the gases are coolest and flows toward the fire where the gases are hotter. In 'other words, the coolest liquid is acted upon by the coolest gases.

In Fig. 6 is shown a Slight'modification of .the heater wherein the coresI for the tubes are mounted in thin metal envelops 39 similar in construction to those referred to in connection with Fig. 4 and for the same purpose. They are alsoprovided with metal ends or covers 40. Normally the heater and also the trap feeding it will be illed with mercury. I

I am of course aware of the so-called capillary boilers for-.water in which the tubes or passages are largely filled with some material to hold the water in boiling contact with the walls of said tubes or passages but the vaporizing spaces in my improved boiler are in no sense capillary in-their nature. In such boilers water has to'be forced under relatively highpressure by a pump through the `passages whereas in my case the feeding of liquid to the vaporizing spaces is solely by gravity. Further such boilers do not have the feeding passages in the coreas herein specified nor the storage space for vapor and liquid.

I have not described the power system to which my improved boiler is especially adapted because it forms the subject matter y of my application for Letters Patent, Serial No. 63,992 filed November 29, 1915. v.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the inventioncan be carried out by other means. What I claim as new and desire to secure by Letters Patent of the United States, is-

1. A boiler for vaporizing liquids, comprising a plurality of heating tubes, and a core for each tube formed of a material which is a poor conductor of heat and which is of but slightly less diameter than said tube whereby a narrow annular space is formed between the outer surface of the core and the inner surface of the tube, said core having a relatively small axial opening.

2. A boiler for vaporizing liquids, com-Y prising a plurality of heating tubes, a core for each tube formed of a material which is a poor conductor of heat and which is of relatively `large diameter, whereby but a narrow spaceV is formed between the `outer surface of the core and the inner surface of the tube, and means for spacing each core relative to its tube, each core being provided paratively narrow annular space is formed between the outer surface of the coreand the inner surface of the tube, said core having a relatively small axial opening com- 5 municating at Aone end with said chamber and at the other with the space between the core and the tube.

4. A boiler for vaporizing liquidsV comprising heating tubes, thin tubular metal l0 envelops located in the tubes and separated therefrom by clearance spaces, a filling of relatively non-heat conducting material for the envelops, each of said envelops and its filling being provided with a longitudinally v extending passage that communicates with 13 the space between the envelop and its tube.'

In witness whereof, I have hereunto set4 my hand this 11th day of December, 1912.

WILLIAM L. R. EMMET. Witnesses: BENJAMIN B. HULL,

HELEN ORFORD. 

